<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>燕云长风</title>
    <style>
        body{height: 5000px;
        }
    </style>
</head>
<body>
     宽&nbsp;&nbsp;&nbsp;：<input type="text" id="width"><br>
     高&nbsp;&nbsp;&nbsp;：<input type="text" id="height"><br>
     面积：<input type="text" id="height"><br>
     <div>我是DIV</div>
     <button id="btn">点击次数</button><output id="cal"></output>
</body>
</html>